If you see the get-member of any cmdlets you may get some properties/methods but that may not be complete to get the complete list of properties and methods use the Format List (fl) option with * .

|Fl*

Profile:

As you know if you declare any variable or script anything that will be valid (available ) until you are using the session, once you close the Powershell session your variables will be lost, to keep the variable or object for longer use, declare it at profile which loads at the time of Powershell start